The Imperative (sometimes called the Imperative Mood)is a form of verb‏‎ in English. It’s used mainly to tell people what to do so we can have different types of imperative sentences:

Giving Orders:

Stop!

Shut the door!

Giving instructions:

Add a pinch of salt and boil for fifteen minutes.

Go out the door and turn left.

Making informal offers or invitations:

Have a drink?

Want a ride?

Giving warnings:

Don’t take lifts from strangers.

Do try to take care!

Form

When we use the imperative we leave out the subject of the sentence‏‎.

You must stop talking!

Stop talking!

You will also see that the form of the imperative is the same as the infinitive.

Stop talking and stand still!

To be polite, we add please to the the sentence:

Please stop talking!

To tell someone we want something very much, we put please or do at the beginning:

Do tell me!

Please tell me!

Do please tell me!

We can use the imperative as a subject of a sentence. We often follow it with and:

{imperative} + {and} + {clause}

Get this done + and + you can leave early.

Complain again + and + we will leave.

BrE vs AmE

In British English two imperatives can be joined by and:

Come and sit here!

Go and wait in the car.

In American English‏‎, the imperative doesn’t always use and:

Come sit here.

Go wait in the car.

Useful Links

The ICAL Grammar Foundation Course – a course in English grammar.

Verb Moods‏‎ – more about verb ‘moods’